The pH value of the rainwater becomes slightly lower than the pH value of the the normal tap water. The ph value of rain water becomes low because of its reaction with which gas ? please answer it briefly with an explanation

Dear student, Pure water has a pH of 7.0 (neutral); rainwater has a pH of about 5.6 (acidic). The acidity of rainwater comes from the natural presence of three substances (CO2, NO, and SO2) found in the troposphere (the lowest layer of the atmosphere). Carbon dioxide reacts with water to form carbonic acid (Equation 1). Carbonic acid then dissociates to give the hydrogen ion (H+) and the hydrogen carbonate ion (HCO3-) (Equation 2). The ability of H2CO3 to deliver H+ is what classifies this molecule as an acid, thus lowering the pH of a solution. Regards,